Please log in

or

Register now for free

or

Choose your profile *

Email *

A valid e-mail address. All e-mails from the system will be sent to this address. The e-mail address is not made public and will only be used if you wish to receive a new password or wish to receive certain news or notifications by e-mail.

Password

Username *

Newsletters

Higher education updates from the THE editorial team

World University Rankings news

If you do not wish to be contacted about offers, products or services from THE/TES Global then please check this box

Drug fails sex drive test

SCIENTISTS from Finland, the United States and Britain have uncovered evidence that contradicts manufacturers' extravagant claims for the aphrodisiac qualities of some popular herbalproducts.

Claims for the effects of yohimbe, a herbal preparation of the African plant Corynanthe yohimbe, are bold. "An excellent approach to sexual rejuvenation," says one supplier. "An African herb with well-documented aphrodisiac effects," claims another. "Lasts up to two hours!" boasts a third.

But new research from the department of psychology atValparaiso University in Indiana and the surgical clinic at theUniversity of Oulu in Finland shows that yohimbine hydrochloride, the chemical extracted from the plant, has no effect on sexual desire or the ability to achieveerection, in either sexually functional or impotent men.

The Finnish researchers say there are many causes of impotence, and that most of these problems can be treated. However, as therapies often require self-injection, clinical scientists have continued to search for alternative remedies that can be taken orally.

By the mid-1980s it was believed that a suitable oral treatment had been found in yohimbine. But while the use of both the prescribed drug yohimbine hydrochloride and its herbal counterpart yohimbe have increased, clear evidence of any real effectiveness in treating impotence has been lacking.

Earlier research had suggested that in some cases, patients receiving high doses of the drug have responded better than those receiving a placebo, according to Alan Riley, senior lecturer in human sexuality at St Georges Hospital Medical School in London. But he stressed that the drug had not been shown to improve sex drive.

"I don't think it has aphrodisiac qualities at all. What it does do is produce erection. It is better than a placebo for this, but not dramatically so. But it has no effect on sexual desire or drive," he said.

The Finns have argued that earlier studies were incomplete. Using a more sophisticated experimental design, which should give a more accurate picture of the drug's effects, they found that while yohimbine had no significant effect on symptoms related to impotence, it did cause serious side-effects in two of patients taking the drug. One suffered a serious increase in blood pressure, the other severe palpitations.

The use of yohimbe as a treatment for impotence was initially adopted as a herbal therapy on the basis of reports of its use in promoting potency among indigenous West African cultures.

There, the bark of the tree Corynanthe yohimbe has been used for centuries in the preparation of a drink used in a number of rituals.

Other plants with reputed aphrodisiac activity includeginseng, avocado, coffee, nutmeg, lettuce, and garlic. Yet of these, yohimbe has become the best-known worldwide.

Since its discovery, yohimbine's formidable reputation has stimulated much attention in the scientific community. Scientists have investigated its chemistry, its effects on the human nervous system, the plants it is found in, and now its role in the treatment of impotence.

However, the Finnish findings suggest not only that yohimbine's longstanding reputation may have little factual basis, but that the drug can cause problems of its own.

In addition to the severe side-effects found in Finland, other reported effects have included eczema, kidney failure andanxiety. This last effect could be of particular significance for yohimbine's value either as a general aphrodisiac, or more specifically in treating impotence.